/*
 * Copyright 2018 Christian Ebner
 *
 * This file is part of dmio.
 *
 * dmio is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * dmio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with dmio.  If not, see <http://www.gnu.org/licenses/>.
 */

#![allow(dead_code)]
#![feature(test)]

extern crate byteorder;
extern crate test;
#[macro_use]
extern crate log;

mod dmreader;
mod dmwriter;
mod dmtypes;
mod taggroup_entries;
mod create_tgs;
#[cfg(test)]
mod tests;


use std::fs::OpenOptions;
use std::path::Path;
use std::mem;
use std::ops;

use taggroup_entries::{Key, Tag, TagGroup};
use taggroup_entries::Key::*;
use taggroup_entries::Tag::*;
use dmtypes::{SORTED, OPEN};
use dmreader::DMImageReader;
use dmwriter::{DMImageWriter, DMImageWriteByVersion};

pub type DM3Reader = dmtypes::DM3Reader;
pub type DM4Reader = dmtypes::DM4Reader;
pub type DM3Writer = dmtypes::DM3Writer;
pub type DM4Writer = dmtypes::DM4Writer;
pub type Result<T> = std::result::Result<T, Box<std::error::Error + Send + Sync>>;

#[derive(Debug, Default)]
pub struct DMImage {
    path: Option<String>,
    root: TagGroup,
    data: Tag,
    sizex: Tag,
    sizey: Tag,
    sizez: Tag,
    version: usize,
    tg_size: usize,
    bigendian: bool,
}

impl ops::Index<[usize; 3]> for DMImage {
    type Output = f32;

    fn index(&self, index: [usize; 3]) -> &f32 {
        let z_offset = index[2] * self.sizex() * self.sizey();
        let y_offset = index[1] * self.sizex();
        let x_offset = index[0];
        &self.data()[z_offset + y_offset + x_offset]
    }
}

impl ops::IndexMut<[usize; 3]> for DMImage {
    fn index_mut(&mut self, index: [usize; 3]) -> &mut f32 {
        let z_offset = index[2] * self.sizex() * self.sizey();
        let y_offset = index[1] * self.sizex();
        let x_offset = index[0];
        &mut self.data_mut()[z_offset + y_offset + x_offset]
    }
}

impl ops::Index<[usize; 2]> for DMImage {
    type Output = f32;

    fn index(&self, index: [usize; 2]) -> &f32 {
        let y_offset = index[1] * self.sizex();
        let x_offset = index[0];
        &self.data()[y_offset + x_offset]
    }
}

impl ops::IndexMut<[usize; 2]> for DMImage {
    fn index_mut(&mut self, index: [usize; 2]) -> &mut f32 {
        let y_offset = index[1] * self.sizex();
        let x_offset = index[0];
        &mut self.data_mut()[y_offset + x_offset]
    }
}

impl DMImage {
    /// Returns the element at given indices by reference.
    ///
    /// Panics if the element at given indices does not exist.
    pub fn ind(&self, x: usize, y: usize, z: usize) -> &f32 {
        let z_offset = z * self.sizex() * self.sizey();
        let y_offset = y * self.sizex();
        let x_offset = x;
        &self.data()[z_offset + y_offset + x_offset]
    }

    /// Returns the number of image pixels on the x-axis.
    #[inline]
    pub fn sizex(&self) -> usize {
        match self.sizex {
            ULong(sizex) => sizex as usize,
            _ => 0usize,
        }
    }

    /// Returns the number of image pixels on the y-axis.
    #[inline]
    pub fn sizey(&self) -> usize {
        match self.sizey {
            ULong(sizey) => sizey as usize,
            _ => 0usize,
        }
    }

    /// Returns the number of image pixels on the z-axis.
    #[inline]
    pub fn sizez(&self) -> usize {
        match self.sizez {
            ULong(sizey) => sizey as usize,
            _ => 0usize,
        }
    }

    pub fn shape(&self) -> Vec<usize> {
        let mut shape: Vec<usize> = Vec::new();
        match self.sizex {
            ULong(sizex) => shape.push(sizex as usize),
            _ => return shape,
        }
        match self.sizey {
            ULong(sizey) => shape.push(sizey as usize),
            _ => return shape,
        }
        match self.sizez {
            ULong(sizez) => shape.push(sizez as usize),
            _ => return shape,
        }
        shape
    }

    /// Returns true if image has endianess `BigEndian`.
    #[inline]
    pub fn is_bigendian(&self) -> bool {
        self.bigendian
    }

    /// Returns a reference to the raw data vector of the image.
    ///
    /// On error panics.
    // TODO impl for other datatypes as well
    #[inline]
    pub fn data(&self) -> &Vec<f32> {
        match self.data {
            ArrayFloat(ref array) => array,
            _ => panic!("Inconsistent data, exiting..."),
        }
    }

    /// Returns a mutable reference to the raw data vector of the image.
    ///
    /// On error panics.
    // TODO impl for other datatypes as well
    #[inline]
    pub fn data_mut(&mut self) -> &mut Vec<f32> {
        match self.data {
            ArrayFloat(ref mut array) => array,
            _ => panic!("Inconsistent data, exiting..."),
        }
    }

    /// The use of this function is deprecated, use the `DMImage::new()` function instead or
    /// operate directly on the data of an opened image
    // TODO impl for other datatypes as well
    pub unsafe fn replace_data_with(&mut self, new_data: Vec<f32>, shape: &[usize]) -> Result<()> {
        match self.data {
            ArrayFloat(ref mut array) => {
                mem::replace(array, new_data);
            }
            _ => {
                return Err(From::from(
                    "Error while replacing the image data, operation not performed...",
                ))
            }
        }

        self.swap_data();
        for (dim_ind, &size) in shape.iter().enumerate() {
            match *self.root
                .get_mut("ImageList").unwrap()
                .get_tag_mut(&Key::Index(1)).unwrap()
                .get_mut("ImageData").unwrap()
                .get_mut("Dimensions").unwrap() {
                TagGroupEntry(ref mut tg) => {
                    let _ = tg.insert(Index(dim_ind), ULong(size as u32));
                }
                _ => return Err(From::from("Unexpected tag type for 'Dimensions'")),
            }
        }
        self.swap_data();

        Ok(())
    }

    /// Creates a new, empty image.
    pub fn new(shape: &[usize]) -> DMImage {
        info!("Called dm3io::DMImage::new()");
        let mut image = DMImage {
            path: None,
            root: TagGroup::new(SORTED, !OPEN),
            data: Empty,
            sizex: Empty,
            sizey: Empty,
            sizez: Empty,
            version: 3usize,
            tg_size: 0usize,
            bigendian: false,
        };

        let app_bounds = Struct(vec![Long(0), Long(0), Long(944), Long(1524)]);
        image.root.insert(
            Key::from_str("ApplicationBounds"),
            app_bounds,
        );
        image.root.insert(
            Key::from_str("DocumentObjectList"),
            create_tgs::document_object_list(),
        );
        let dt = TagGroup::new(SORTED, !OPEN);
        image.root.insert(
            Key::from_str("DocumentTags"),
            TagGroupEntry(dt),
        );
        image.root.insert(
            Key::from_str("HasWindowPosition"),
            Boolean(false),
        );
        image.root.insert(
            Key::from_str("Image Behavior"),
            create_tgs::image_behavior(),
        );
        let image_type = 2u32;
        image.root.insert(
            Key::from_str("ImageList"),
            create_tgs::image_list(shape, image_type),
        );
        image.root.insert(
            Key::from_str("ImageSourceList"),
            create_tgs::image_source_list(),
        );
        image.root.insert(
            Key::from_str("InImageMode"),
            Boolean(false),
        );
        image.root.insert(
            Key::from_str("LayoutType"),
            ArrayUShort(vec![85, 110, 107, 110, 111, 119, 110]),
        );
        // TODO It seems that this stuff is not needed neccessarily, remove it completely if that
        // is indeed the case
        //image.root.insert(Key::from_str("MinVersionList"), create_tgs::min_version_list());
        //image.root.insert(Key::from_str("NextDocumentObjectID"), ULong(9));
        //image.root.insert(Key::from_str("Page Behavior"), create_tgs::page_behavior());
        //image.root.insert(Key::from_str("PageSetup"), create_tgs::page_setup());
        //let sl = TagGroup::new(!SORTED, !OPEN)
        //image.root.insert(Key::from_str("SentinelList"), TagGroupEntry(sl));
        image.root.insert(
            Key::from_str("Thumbnails"),
            create_tgs::thumbnails(),
        );
        //image.root.insert(Key::from_str("WindowPosition"),
        //    Struct(vec![Long(62), Long(20), Long(190), Long(148)]));
        image.swap_data();

        image
    }

    /// Opens and reads an existing DMImage given by the path and returns it as `Result<DMImage>`.
    ///
    /// If open fails, an std::io::Error is returned.
    pub fn open(filepath: &str) -> Result<DMImage> {
        debug!("DMImage::open({})", filepath);
        let path = Path::new(filepath);
        let file = OpenOptions::new().read(true).open(path)?;
        // Load the full image into memory and parse the image content
        let mut reader = DMImageReader::new(file)?;
        let mut image = reader.parse()?;
        // Swaps the data to the DMImage handle for faster access,
        // this needs to be reversed before writing the image to file
        image.swap_data();

        Ok(image)
    }

    // TODO impl this
    // fn save(&self) -> Result<usize, Error> {
    //
    // }

    /// Save DMImage to file given by filepath.
    pub fn save_as<R: DMImageWriteByVersion>(&mut self, filepath: &str) -> Result<()> {
        debug!("DMImage::save_as({})", filepath);
        let path = Path::new(filepath);
        let mut options = OpenOptions::new();
        let file = options.create(true).write(true).truncate(true).open(path)?;
        // Need to swap data back into the root before saving
        self.swap_data();
        {
            let mut writer = DMImageWriter::from(self);
            writer.write_to_file::<R>(file)?;
        }
        // Now that the data is written, we switch it back from the root
        self.swap_data();
        Ok(())
    }

    /// Returns the smallest value in the image.
    // TODO impl for other datatypes as well
    pub fn get_min(&self) -> f32 {
        let mut min = self.data()[0];

        for val in self.data() {
            if *val < min {
                min = *val
            }
        }

        min
    }

    /// Returns the smallest value in the image.
    // TODO impl for other datatypes as well
    pub fn get_max(&self) -> f32 {
        let mut max = self.data()[0];

        for val in self.data() {
            if *val > max {
                max = *val
            }
        }

        max
    }

    /// Returns the image as rgb values in a raw vector `Vec<u8>`.
    // TODO impl for other datatypes as well
    pub fn to_raw_rgb(&self) -> Vec<u8> {
        match self.data {
            ArrayFloat(_) => {
                const RGB_BITS: usize = 3;
                const DEPTH: f32 = 255.0;

                let mut buf = Vec::with_capacity(self.sizex()*self.sizey()*RGB_BITS);
                let min_val = self.get_min();
                let max_val = self.get_max();
                let slot = if (max_val - min_val).abs() < std::f32::EPSILON {
                    (max_val - min_val) / DEPTH
                } else {
                    1f32
                };

                for val in self.data() {
                    let temp = (val - min_val) / slot;
                    let grayvalue = temp.trunc() as u8;
                    // Push RGB values
                    buf.push(grayvalue);
                    buf.push(grayvalue);
                    buf.push(grayvalue);
                }

                buf
            },
            _ => panic!("Inconsistent data in `DMImage::to_raw_data()`"),
        }
    }

    fn swap_data(&mut self) {
        match self.root
            .get_mut("ImageList")
            .unwrap()
            .get_tag_mut(&Index(1))
            .unwrap()
            .get_mut("ImageData")
            .unwrap()
            .get_mut("Data") {
            Some(ref mut tg_data) => mem::swap(&mut self.data, tg_data),
            None => panic!("Inconsistent data, exiting..."),
        }
        if let Some(ref mut tg_sizex) =
            self.root
                .get_mut("ImageList")
                .unwrap()
                .get_tag_mut(&Index(1))
                .unwrap()
                .get_mut("ImageData")
                .unwrap()
                .get_mut("Dimensions")
                .unwrap()
                .get_tag_mut(&Index(0))
        {
            mem::swap(&mut self.sizex, tg_sizex);
        };
        if let Some(ref mut tg_sizey) =
            self.root
                .get_mut("ImageList")
                .unwrap()
                .get_tag_mut(&Index(1))
                .unwrap()
                .get_mut("ImageData")
                .unwrap()
                .get_mut("Dimensions")
                .unwrap()
                .get_tag_mut(&Index(1))
        {
            mem::swap(&mut self.sizey, tg_sizey);
        }
        if let Some(ref mut tg_sizez) =
            self.root
                .get_mut("ImageList")
                .unwrap()
                .get_tag_mut(&Index(1))
                .unwrap()
                .get_mut("ImageData")
                .unwrap()
                .get_mut("Dimensions")
                .unwrap()
                .get_tag_mut(&Index(2))
        {
            mem::swap(&mut self.sizez, tg_sizez);
        };
    }
}